SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21bd58317a844bfec7946852b90238cbed7514d779f4fee9927f8d2136890b92' 
  AND token = 'IlmyE+M9KqJVjSpdRY3+q7zsBLbDeOJaj1y8npD6hmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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