SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b5dfea75883d9b96442f0ca83cdda4e7400d310dad3f7fcaba0fd8105bfe18e' 
  AND token = 'uvcUyY+KAv28OzgvpRykjo8fcG/JChCdfvAsVcnEoQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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