SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83a9c7b0ab144622992b37445530b0e2c5835d991b3caa3bd77824082f2c3caa' 
  AND token = 'OzJzymJt4wLnQ6H8pPNreQocjKtkOaniTRZpvueytaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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