SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3851f171d2bacc5d785446ae6d434208ff10aaa73e3eb921dc28e2f908c7e8a' 
  AND token = 'ajdDMMexRC5ZsJ4/W3X6RH4Lb19tuxy6VjQQB33oUsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}