SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd59fcadea03e336b8b37c40e5877ab9c6dc157558138132c840caaba6b4ed620' 
  AND token = 'CtgbPZBeOtCSN47o3wxFEjkxTeF3ceHuVl5GqVZBRU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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