SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e768f7d591fadaeb01d7c1a217cf142dc7a12a20f92190e80462e0c5f064def5' 
  AND token = 'azHz6Il1MHs1FGeCCPB8yOCprU9IFwcsD5rySKm8CtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}