SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4fb37ce9461dad89304249e0098e261b1ba2c3bd487552b5ef83bd9c9f875ab' 
  AND token = 'iorctlb5qWVx61H2401ATNtCf0hITFl0MMSHDePtPjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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