SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d78b54dd6883a06ab83fa01f80adbfa3e8d172d13ef115d7c90fc7429b43f9c' 
  AND token = 'UK+bwTmUTnH+SsArrT3whRETOZCbGm78dyn3PFvyFrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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