SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '711dfdb545f586972c9b6741e2d1a1579c1038439862fbae5855866dce561584' 
  AND token = 'PBdqDIlRb/R9zgTyGRjdMcx54zZUAG+57LATJYKPIY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}