SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5d462507dd3cb27eb64e93c69ca65cdb26ead7893960eb19f42fd4a1695b7ce' 
  AND token = 'DMZer8czL5QxkDE2zS1mKg5YQjrVvekTn+dqIDm4eFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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