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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e359841233d9596b01a93f95fadc52edaa847dc0c1b6b1797a97963e71edd09' 
  AND token = '3eth5849qXDZHU00Qs4lkrqjbAy314pExdiFNDPr2tc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}