SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c445652e97959e8f1e417ce3f6cde9a2eb7509ac7bcad13816ca3fbde5a5a595' 
  AND token = 'SU2U5LqbSjgtGK64p+vYJVZwYGl+0RQ5jLSjpF4HGYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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