SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4e3301aea8ec768458fb112cd0fe2c49324a35e00fdfa7af17d19384110b615' 
  AND token = 'V2DUsc1UBEqCiflVruOym4CUEemVmb8+fnBArwLtz48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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