SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '894744e8f14767daf30fbfa534d67b10ffce00911a1f106720084565ff6d87cb' 
  AND token = 'fgvJnOpSYw+Ur4i95WWI0KUAypq2D6ajxck2+7DiQp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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