SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1968a92e8956fcea5b1c5e964ab57eb04392e9f9e0dfef2fc60d1e17250d0e25' 
  AND token = 'StgjMKzeo2oKaGscfbb+vqvyHJDB2s+pgw0ihWwsrds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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