SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb35ecc4ade9f81eade1b492db654d2e02045f260982aaf9a84dde9bd693e4ac' 
  AND token = 'LXu35O0n5kmhcdet7biW3wvC/ZOURmDhTSklwJXYFPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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