SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c77370973684ab65abd85feb47da8dfc8e035d5821c3e8a47088e728e2142ff7' 
  AND token = 'uTxppG6T8C7qg4zuHvMDAUpbwvnNeh+5IfFchrDYglE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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