SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1ec1484c372118b47404a5fb9e26c5dd6d495ef817b498da8be5ac9d7727314' 
  AND token = '7c47xPz17OZ2pf6PGxBt9CJRyOJsIy4YPhRRtL+MUsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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