SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30b78137bdf1473fd5729b3da391ce841ea74936c06f7cb41bf55c61d64aca5d' 
  AND token = 'nYkgtXM3+6IwzoF19z5ZI8sgBjg9tirvg0wK/bA30Lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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