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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ab9a6888eb8efbbf0820d0298e264dc1412b1c647aa5ce14c1c0369cbc5a0df' 
  AND token = 'eCtJpgFDc5BvD5FeRJ0Xz/vdadBL0o2k6oNAlKItMwc=' 
  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"
    }
  }
}