SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1883859cd88b2501484981fe30014e60fb3866102b5ea62f8264fa439d3e18f8' 
  AND token = 'qs3EhF1DKfQrTwDnygV/my0odhq9hbe/v83/wX3M+Mc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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