SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8985d51da305401129bd8b1aebdf44d460ba6d8375666721d610377794aaf285' 
  AND token = '4re/+yBJWIcWm5OHpGlgP3DOg9xHGDB1jhDOjJE8Rcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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