SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42062bf478291fa8d06562300fecd012de825c34ba38a302682d3a7cb9658b84' 
  AND token = 'ab5TJv0z2QCzHf2H/ncA/amKxgd62cLcuiU48dG1UuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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