SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5251c4c8731c032b03229b467a8c7c0cbed1b0830fea4552a903954ffefc4ae4' 
  AND token = 'rO1VkTa/s80BZYV2XpbZWX1aqaoC/UEiSbkgj92Ci/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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