SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcb1749e473ce66c09968c99ff47ee1ebd5f3ab574c4e7722be1724f574165e8' 
  AND token = 'paPQGf4wfWNFD0usYYnfNmRaH/y7UECmc6gzwUTrNww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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