SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac2491c877b92895b6b9124ee810201828bc1eb65b146022bd722a14b943d13b' 
  AND token = 'FQYWX0HdK1aEk0emmEaSRV5qSX2bKNoPMULN+vKwQKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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