SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4b94f7de7f8552f55b775c4e1b9fdd5544186656dd6e63409bb7b9b16d334a6' 
  AND token = 'u1DFDhJRe/HlmSCDLx8+mGaNLd3jpBFZ7YlmqEm5/Ds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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