SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deaf566e995149497a8018bb5b4170592ded5ef89d6b7c385db1a5913a4448e9' 
  AND token = '3fOyK+vd4Y6vWynPNdXf+ubRbFpUAoVYwdyQvGrY+XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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