SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fd6c8dd6db1ff7ca1ffe5280bd1c51029fdce4d79c9c9e508dbbfe5a86534e7' 
  AND token = 'J53ZlEdlxTctwaW4gA7nu2zEHvPTEEvCuTHIrc7NxzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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