SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2398e46b97ae6cbd68763b5709937479157d48083ada9ad1bc1f9b2a1ec9aed4' 
  AND token = 'MWRXUUf1wxLd4GqeRQB40jXpyrZLmlW8X2/wnXQm7/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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