SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5be21c8b3c910eaff4bddab2bc2d608bbc7d0ba76e9e003958cd1e064c7430a' 
  AND token = 'Z4U5aEqn+mb/ShZYCMClhRoj/GHSKXMl9hvGR7sihYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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