SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0ec2ba033587d108d6e27404e9ba74d424eef3b9587789fda8761b5adff768c' 
  AND token = 'n4m+bEcSPnwkLmY6aJfzbKHWemp4n7vfJbTPIuCCRSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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