SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80fb0bb9567ed2347315178deedaf6850f68f82ff7f85a5938fddd57698d236c' 
  AND token = 'qG7EvC1iAkskjByzgDnOTmHY3N2lVk+7XWCCsqLhjIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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