SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1ec52f384a813e0138603c5fce5a806d0a6158afb46761870a460fc10c6fc3d' 
  AND token = '71JFeWY4yhlzIKQKEeOdb9Sb1Co0/LhvNJhKGYNkONY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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