SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd51a42fe9ffc787290c71c7600236c100f0ba2bbf7ea6f00e2827fb70b2906ae' 
  AND token = 'v27QV7Qi15hp91vDpfIeDNvJGuWFphm5Grpb2AGEh6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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