SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6454c2af58ce5932e1916e821ff596c8f2c835bb862890e7580ddcba00ff4481' 
  AND token = 'jLx7TP/Nnx2cFWeetuVPF+TG0UEHJF0nfhkzeM/Cshk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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