SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8f1dc3bcc49e3752ccdd164e37f816d4406086d51d6816a49fb3827e0bf483f' 
  AND token = 'Q2Z+Xpbu0sIF3vTctgaU+W5lnQZwHYcsWqGk2e9hBy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}