SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57b97703b754727fdabc94b9aa5e93c55ffa510da78d86981f3550e302731ba0' 
  AND token = 'SfHT6e7kiUAu0UCv/ONVQXSBW/p8z/dQFacxwXEhFqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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