SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e845f0e876c6aba16051b6a091f2969d71f9e88ddbca8caa2e08e7d1f21fd4c1' 
  AND token = 'lsscL9J+PI68l8cK4axuG9s8v7BfgpOA9epafxo0B7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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