SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f4a1b32788e48caa58b194bcf8a9e91f900dc60c8a78b740ded6baf35bce6ee' 
  AND token = '/wWlKIPPXtaLyUfPMzIzanGPTvXyIUH/hthuooJweWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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