SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '812a399b45f2244a2357398ca090d870c3963d6594773a32445300c1dc0c5264' 
  AND token = 'XscyCR571nWd1V2JevlG7tvJa1ZcwaVkhjgC/5VElWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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