SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4051d773d5701387e227b9dc817740a234631159d7df5ce8cbbd1f13486c29b' 
  AND token = 'FhuhslemFXCVnH0zhp63LUYpYsD8HBcGfPBcYfuRjl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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