SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '459ba1cfbc79577fae7d253cbfff2bd7620d82f914cff999fbafc3426b93d4f1' 
  AND token = 'flVJFo4WNB5/jMi+lI37cdDyuewPtpFmxSgmPr5BPIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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