SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c4284d491a2b07b51efccaf2e8a42ffb2be1cdcc1f917cdf178f7543fe8ac46' 
  AND token = '7oO4vSTKvm1zwiX/91iVZbh0wcsST4BAqrEabweM6WE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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