SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17c2eef9ad6da014343c32581dc7276259fd962e2a57e409bd516057dbe8d4e2' 
  AND token = 'yuV1PsNAFIO7t80GsLOtzTx+G37bVm7rOMo0gHOiO8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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