SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '012f94eff4934aeb9a130c517cd9787d335bb9b70550331e83497389f019cf55' 
  AND token = 'R/pilqPDID+P+gUUW4BvjMDv6W+XdTwFGo4eaPslZms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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