SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b78f94000edf7991a306836cdffd3e6dc035a14ea36193dc9dcc89cdfa6b8711' 
  AND token = 'PMBA23GwEN0aHp9j5mRgA76D7meQOVu860i7il6EkGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00099

JSON explain

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