SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '536be08b910d832d7defd3a88286b9577b6a4a123f970b1e19bc996637f8a465' 
  AND token = 'UIfqCxc07vhSUScA0ao4fdjAYaHO0ywFfjPW3bpTY1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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