SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75a532bc0c5505a1a30c9ba698ff645a89ee3c09d1ce055bf880865e8d46567c' 
  AND token = 'FpbQjoGSUFbKINQqQYmHpE+BijwJdZZpHjxowX+oxzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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