SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb367a83e46db8ec70e289b260a84c889b77328cc6f92642f543833ca81891c3' 
  AND token = 'I4iOuMGODknzjSM/L2huqNjUfbSPrqrhRAMAtEQFLKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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