SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c88e47fe6647f273ce163f28f703446bb851b830619f82b51f6d01cdd150f88' 
  AND token = 'UbNBalBO+ro05+96BfZfCZ9LU9h1iEzzddxzWAuafkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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