SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e86ad7cc2b1d9a5d09315b1b6184642e2e6973908ba599780aaddd93c1febcc' 
  AND token = 'eT6pzm5luOm2vzB35D4HilGOGXYAQMsT1Mu3hSCO6Pk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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