SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c339d3b27deb90d7145fd9a96da2a5e8e1cd80fdc6a7979b436e4d5176cf2554' 
  AND token = 'SPNs9xK4bUIUfhvscZqPL5ewepIo7T0cMWH/oKJ6Yeo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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