SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4636beecd1d710314a0310d7cca8af73f2c8e0f605f524746b0a86104fc826b9' 
  AND token = 'fPfsgso5fQ/Udb1xjIRUbiw3wkFfHkN08hD0/I05LyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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